Abstract
Introduction: A cementless femoral implant is currently available for hip resurfacing with several theoretical advantages over cemented fixation, one of which is a potential reduction in systemic emboli. A prospective study was undertaken to evaluate the occurrence of systemic emboli using a cementless femoral component for hip resurfacing in comparison to cemented femoral fixation.
Methods: Between November 2004 and December 2005 patients scheduled for elective hip resurfacing for osteoarthritis were consented to undergo hip resurfacing using a cemented femoral component (Articular Surface Replacement or Birmingham Hip Resurfacing) or a cementless femoral component (Bi-coat Cormet Hip Resurfacing). Each case was randomised to femoral venting or no femoral venting. Intra-operative monitoring with a Transcranial Doppler device was used to identify and record systemic emboli throughout each case. Demographic and peri-operative data were collected including mental score and vital observations at day 1 and day 3, and blood loss.
Results: 8 patients (5 vented, 3 unvented) underwent cemented resurfacing and 7 patients (4 vented, 3 unvented) had cementless resurfacing. There was no difference between the two groups for age (mean 56yrs), gender, weight, or ASA status. The mean number of significant emboli (> 12dB) in the cemented group was 8.1 and in the cementless group was 1.7 (significant, p=0.009). Peri-operatively both groups were similar for vital observations, haemoglobin, mental scores and SaO2. Venting did not influence rate of emboli. However, venting was independently associated with significantly higher drainage (mean 604mls compared to 335mls without venting, p=0.018).
Discussion: This study has shown significantly less systemic emboli occur with the use of a cementless femoral component during hip resurfacing in comparison to a cemented implant. We propose this is due to intra-osseus pressure generated when using cement. The number of emboli is unaffected by femoral venting, but more blood loss occurs after venting.
Correspondence should be addressed to Mr John Hodgkinson, BHS, c/o BOA, The Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London WC2A 3PE.